<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
<!--    <link rel="stylesheet" type="text/css" href="mixin.css">-->
    <link rel="stylesheet" type="text/css" href="extend.css">
</head>
<body>
    <div id="wrap">
        <div class="inner">inner1</div>
        <div class="inner">inner2</div>
    </div>
</body>
</html>